I downloaded and installed dbMonitor, and it was working fine. I did not deliberately change any settings, but now the only thing that dbMonitor shows is a message "dotConnect for Oracle monitoring is started," everything else it used to show (SQL statements, etc.) is missing.

Any idea what might have been inadvertently changed to hide or eliminate all of the important stuff?

I found the problem, I wrote a Winforms app and declared the OracleMonitor object in the forms class - when I moved it to the static class in program.cs everything started working again. Sorry if I sent anyone on a wild goose chase.